Creation of magnetic monopoles in pulsars

Abstract

THE symmetry of the free Maxwell equations under transformation of electric field into magnetic field led Dirac¹ to suggest the existence of magnetic monopoles. Many experimental searches for these particles have been made on different accelerators and using cosmic ray interactions; no magnetic monopoles having been detected, upper limits of the cross sections for the creation of monopoles have been obtained. The data of Ross et al.² are the best and can be fitted by: where σ_pn is the proton–nucleon cross-sections in cm², and m_g the monopole mass in GeV c⁻². It is believed^3,4 that very energetic particles are created in pulsars. These particles can interact between themselves and/or be smashed onto the neutron star surface to produce pairs of magnetic monopoles and antimonopoles. These monopoles (if they exist or are effectively produced) would be accelerated in the pulsar magnetic field, one species towards the interstellar medium, the other towards the neutron star, producing a decrease in the magnetic field. Such a phenomenon can be related to observations, particularly to the discrepancy between the characteristic and the kinematical ages. We show here that these observations can be explained by a production of magnetic monopoles, inherent to the pulsars, with a cross-section lower than equation (1), (that is, without contraction with the negative results of the terrestrial searches). More specifically, we will consider the magnetic monopoles production on the neutron star surface, in the Ruderman and Sutherland model⁴. Other models (with and without gaps) will be considered elsewhere.